The present invention relates to an imaging device that is used for, for example, a digital camera, a digital video camera, a device that obtains an image (image data) such as an image-reading device, and the like. In particular, the present invention relates to an imaging device that is suitable for an in-vehicle camera.
Conventionally, an imaging device having an optical element such as a lens for imaging, or the like, and an image sensor such as a CCD (Charge-Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), or the like, is widely applied to a digital camera, a digital video camera, an in-vehicle camera, or the like. Generally, the imaging device is positioned in a state such that an image-forming position of the optical element (lens) is on the image sensor (light-receiving surface), and is housed in a case.
Regarding such a positioning and fixing method, Japanese Patent Application Publication number 2005-101711 proposes an imaging device in which a screw thread provided on an outer circumference of a lens holder that holds a lens screws a screw groove provided on an inner circumferential surface of a frame (referred to as a lens barrel 4 in Japanese Patent Application Publication number 2005-101711) joined to a substrate having an image sensor. In such a conventional imaging device, an interval between the lens and the image sensor in the direction of an optical axis is adjusted by rotating the lens holder and the frame relatively. And by welding the lens holder and the frame in a state whereby positioning and fixing (focus adjustment) of the lens and the image sensor is performed, the lens holder and the frame are positioned and fixed more firmly. Therefore, it is possible to obtain a more stable optical performance.
Additionally, in Japanese Patent Application Publication number 2005-217500, an imaging device has been proposed in which a cylindrical lens is fitted in a v-shaped groove provided on a mounting base and fixed, and a package of a solid-state image sensor is pressed to each end of three convex parts of a cylindrical member provided in a concave part of the mounting base, each end and a contact portion of the package are melted and adjustment of the solid-state image sensor with respect to the lens is performed, the melted portions are solidified in a state where positioning is performed, and thereby the mounting base and the solid-state image sensor are positioned and fixed more firmly. In such an imaging device, in addition to an interval in the direction of the optical axis, a positional relationship in a direction perpendicular to the optical axis, a relative inclination of a lens with respect to the direction of the optical axis, or the like, can be adjusted. Therefore, a higher adjustment accuracy can be obtained, and a more stable optical performance can be obtained.